OCaml has quite nice JavaScript integration; it has the ability to interact with JS objects, constructors, DOM objects, etc. See the "dom bindings" thread elsewhere in this discussion.
Most other AltJS languages I've seen are primarily based around FFI declarations, where all interaction with JS is done via functions declared in the native language as external and implemented in JS.
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OCaml has quite nice JavaScript integration; it has the ability to interact with JS objects, constructors, DOM objects, etc. See the "dom bindings" thread elsewhere in this discussion.
Most other AltJS languages I've seen are primarily based around FFI declarations, where all interaction with JS is done via functions declared in the native language as external and implemented in JS.